Gaseous conduction device



Dec. 14, 1937. R. E. BARCLAY GASEOUS CONDUCTION DEVIQE Filed Jan. 15, 1934 w W U;

Patented.

UNITED STATES PATENT OFFICE,

GASEOUS CONDUCTION DEVICE Robert E. Barclay, Chicago, 111., assignor to Federal Electric Company, Inc., corporation of New York Application January 15,1934, Serial No. 106,670

35 Claims. (Ci. 1'l6122) My invention relates in general to the electrical discharge art and has more particular reference to lamps and similar devices operated by electrical discharges in an ionized path, the present 5 application comprising a continuation in part of my co-pending application, Serial Number 540,950, flied May 29, 1931.

When an electrical potential difference or voltage of sufficient magnitude is applied at spaced points in an ionized field, a discharge occurs whereby the field is caused to glow and to emit light rays. Various gases, such as neon, argon, crypton, carbon dioxide, mercury vapor, and the like, may be utilized to provide an ionized path for the electrical discharge, and my invention has particular reference to a luminous element of novel construction and adapted for use in various types of illuminating devices, including lighting devices, display devices, signs, and the like, the general object of the invention being to provide a device in which the discharge may be initiated and maintained in operation at relatively low applied voltage.

In the past, it hasbeen necessary to utilize relatively high electrical potential difference to cause an electrical discharge through a gaseous path between spaced electrodes. The necessity of high voltage in the initiation of an electrical discharge is a well recognized draw-back in the commercial operation of electrical discharge devices, and, therefore, my present invention contemplates the production of electrical discharges at low voltage and the resulting commercial advantages flowing therefrom.

One of the important objects of my present invention is to produce an electrical discharge device adapted to be placed in operation at voltages of the order prevailing in the ordinary commercial power circuit.

Another important object of my present invention is to provide a device of the character mentioned, adapted for detachable insertion in a socket in much the same manner that incandescent lamps are mounted.

Still another important object of the invention is to provide a discharge device having exciting means operable to permit the device to be started in operation at relatively low applied voltage.

Another object is to utilize condenser means formed in electrostatic relationship with respect to a discharge-carrying medium in a device of the character described, together with means operatively associated with the condenser means for exciting the medium to permit the device to be discharge lamp combination wherein high freelement.

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placed in operation at relatively low applied voltage.

Another important object resides in providing a quency capacity effects may be applied in the lamp in order to improve its operating efliciency. Another important object is to provide a lamp combination wherein an exciter comprising a conductor is arranged in position to induce high frequency electrostatic effects in the lamp in order to improve its starting and operating efliciency.

Another object is to form a discharge lamp with a substantially U-shaped discharge channel and encircle the same with an exciter comprising a coiled conductor adapted to carry high frequency electrical oscillations in order to permit the U-shaped lamp to be started in operation at low applied voltage.

Another important object is to improve the operating efliciency of an electronic discharge lamp by encircling the path of the discharge with a high frequency electric circuit, specifically by coiling a conductor around said discharge path preferably in the form of a helix and by establishing high frequency oscillations in said helical Among the other objects of the invention are to provide means for ionizing or exciting the discharge path suificiently to permit the discharge to be started at a voltage substantially less than plish numerous valuable advances in the technique of electrical illumination which will become apparent as the invention is more clearly understood from the following description, which, taken with the accompanying drawing. discloses a preferred form of the invention.

Referring to the drawing:

Figure 1 is a vertical section through a low voltage luminescent element or lamp embodying my present invention;

Figure 2 is a cross section through the device shown in Figure 1;

Figures 3, 4, and 5 are vertical sections similar to' that shown in Figure 1, showing modified constructions embodying the invention;

Figures 6 and 'l are views, the one in section and the other in exploded perspective, showing the details of an improved electrode construction which may be used in place of in Figures 1-5; and

Figure'll shows a modified electrode arrangement.

To illustrate my invention, I have shown in the drawing, lamps adapted for use in electrical discharge illumination. The lamps shown are characterized in that the discharge is created through a channel having a plurality of parallel l0 and adjacent channel portions, although obviousthose illustrated sarily restricted to'the specific channel arrangement shown.

The. lamps illustrated comprise preferably glass envelopes H providing longitudinally extending channels i 3. In the embodiment shown in Fig uresl, 2, and 4, the channels are of semi-circular, cross-sectional configuration and are formed side by side within the outer wall l5 of 0 the envelope and separated by a common partition H, the channel portions communicating at the top to form a single discharge channel I8 shaped substantially in the form of an inverted U. in the embodiment shown in Figures 3 and 5 5', the channel It! is formed simply by bending a tubular member i9 aboutits mid-section 2| to provide the substantially parallel and adjacent arms l3. The embodiment shown in Figures 6 and 7 may be incorporated in either lamp form shown.

The envelope H, of the Figures 1, 2, and 4 embodiments, may be made from standard glass tubing by inserting a partition into the tube and fusing its edges to the walls of the tube at I, by means of heat, or the partitioned member may be moulded with an integral partition in the manner described in my United States Patent Number 1,904,348, issued April 18, 1933, or formed in any suitable manner.

In the embodiment shown in Figure 1, the upper end of the envelope is provided with' a. dome 22, which closes and forms a connection between the upper ends of the channels. The lower end of each channel is sealed in any usual or preferred manner and provided with an electrode 23 preferably disposed in an electrode housing It sealed to and forming a continuation of the envelope ll. Each electrode has a connecting conductor extending out of the envelope to form a connection in an external electric power circult. The lower end of the envelope, however formed, may be set in a lamp base 25 of any usual or preferred construction whereby the lamp may be connected in an outlet socket, the base providing terminals 21, to which the outwardly extending connections may be attached, and the envelope being anchored in the base in any suitable manner as by the insulating compound 29.

The embodiment shown in Figures 3 and 5 comprises an elongated tube sealed and provided with electrodes at its opposed ends, the electrodes having connecting conductors extending out of the envelope to facilitate connection in an external circuit. The tube also is preferably, though not necessarily, bent at its mid-portion 2| as shown to form a U-shaped channel with the arms I3 of the channel, juxtapositioned to permit reception in a shell-dike support base. If desired, however, the invention may be applied in a device having a straight channel.

The parallel channels l3, as aforesaid, are preferably connected at their upper ends by bent mid-portions 2! of the tube' l9, or by the dome 22 to form a U-shaped channel t. T c a ly certain phases of the. invention are not necesenvelope, which opening, after the tube has been 'sufliciently evacuated and filled with its gaseous content, may be sealed off to form a rounded point 3|, as is well known in the glass-blowing art.

.To render the luminescent element operable from a low voltage source of electricity, I arrange in or adjacent the channel portions iii an exciter 33 preferably comprising a length of wire, the opposite ends of which are disposed in the discharge channel sufficiently close to the electrodes 23 to permit a, low voltage current to cross the gaps 3'! between the wire and the electrodes so that when low voltage power is first applied between the electrodes 23, a current of electricity will fiow, between the electrodes, through the wire or ionizing element 33 and the gaps 31 rather than through the gaseous medium within the channel, since the path provided by the medium does not become current conducting to a degree greater than the path provided by the element 33 and the gaps 31 until after the medium becomes ionized. The current flowing in the ionizing element 33 will comprise high frequency oscillations due to arcing at the gaps. During the initial discharge, the end of the element 33, adjacent the negative electrode, functions as an anode, while the other end of the element, adjacent the positive electrode, functions as a cathode with accompanying cathode glow. The glow may spread along the element 33 and ionization of the gaseous medium occurs in the space between the electrodes normally occupied by the positive column under normal operating conditions. Eventually, when a sufficient degree of ionization has obtained, most or all of the current leaves the. path including the element 33 and adopts the path through the gaseous medium between the electrodes. This, of course, is due to the fact that the gas has a falling voltage characteristic as it becomes excited or ionized, while the starting path through the element 33 has a substantially constant or rising characteristic. In some cases the starting path may have a slight falling characteristic providing the voltage characteristics of both paths are convergent within the range of current values from zero to normal operating current.

Any suitable conducting material may be utilized for the element 33, although I prefer to select one having as low a cathode fall of potential as will take the starting current for which the unit is designed. Where the unit is to be started on a line potential of the order 0. fiO volts, the element 33 should have a cathode potential drop of the order of less than 120 volts. As shown in Figures 1, 2, and 3, the ends of the wire, and, in fact, the intermediate portions, may be held in place by gobbets 35 of glass formed on the Walls defining the channels. If desired, the wire may be embedded in said walls with its central portions extending parallel to the channels l3.

In Figures 1, 2, and 3, the exciter wire extends in the discharge channel l8, being looped over the envelope portions forming the separating partition between the legs of the channel.

In Figure 4, the exciter comprises a wire coiled in preferably helical form and encircling the outer walls of the envelope ll, both arms of the U shaped channel extending within the coiled exciter wire. The opposite ends of the exciter wire are extended within the discharge channel in the vicinity of the electrodes 23. Obviously, the external arrangement of the exciter wire 33 may be applied in the form of an envelope shown in Figure 3 as well as in the form having the integral partition I! as shown in Figures 1 and 4.

It should be noted also that in the arrangements illustrated in Figures 1, 3, and 4, the exciter wire encircles the partition means separating the legs l3 of the discharge channel.

The electric current flowing in the wire 33 may also give off some heat into the discharge channel portions which will assist in exciting the gas. After the discharge path has been sufllcientiy ionized, its resistance to current flow between -the electrodes 23 will be lowered substantially below that of the exciter wire 33 and the gaps 31 intermediate its ends and the electrodes with the result that an electrical discharge will be created through the gas, the electrical current flowing through the ionized discharge path rather than through the relatively high resistance path formed by the wire 33.

The purpose of the exciter element 33 is to provide'high frequency current oscillations in the vicinity of the channel i8 and thus excite the discharge device to permit discharges to be initiated through the channel l8 between the electrodes 23 at substantially lower applied voltage between the electrodes than is necessary where the device is operated without the influence of the exciter. It is thought that the envelope portions, forming the separating partition between the channel portions i3, provides an electrostatic dielectric forming a condenser and that the high frequency oscillations developed in the exciter conductor 33 upon the initiation of arcing at the gaps 31, in conjunction with the condenser means formed in the envelope, results in the production of an electrostatic effect within the discharge channel resulting in the excitation of the same to a point permitting discharge to occur through the channel between the electrodes 23. The exciter wire may, of course, be powered in any suitable manner to initiate the high frequency current oscillations therein and it is not essential to actuate the same from the electrodes 23 through the gaps 31 since the ends of the conductor may, of course, be connected to any suitable device for initiating the channel exciting oscillations therein from any suitable source of power and I especially contemplate the possibility of energizing the exciter 33 by connecting it with a suitable oscillating circuit powered from a source other than the electrodes 23. The arrangement illustrated. however, provides a compact self-contained means for energizing the exciter.

I also may increase the electrostatic effect of the exciter by interposing a layer of metallic substance between the coils of the exciter and the walls of the envelope H, which the exciter surrounds.

In Figure of the drawing, the exciter wire 33 is applied to a device in which the envelope is formed as a tubular element, the opposite ends of which are sealed and provided with electrodes 23. The exciter wire 33 has one end exposed within the envelope in closely spaced relationship with respect to the electrode therein, the intermediate portions of the wire being coiled around the tube while the opposite end of the exciter wire is exposed in the opposite sealed end of the channel adjacent the other electrode.

Any suitable form of electrode may be employed in the devices illustrated in Figures 1-4, although I have shown electrodes of the form shown in my co-pending application, Serial Number 570,717, filed October 23, 1931, since I find that these are eminently satisfactory.

In addition, I may provide means for heating the electrodes-in order to promote the discharge, since I have found that the electrical discharge in the channel is facilitated by energizing the electrodes in this fashion. The electrodes may. of course, be energized by heating the same in any suitable manner and I may accomplish this by arranging a conductor 39 in inductive relationship with the electrodes and by passing an electrical current through the conductor, the conductor being connected to any suitable source of power. In this connection, I contemplate energizing the conductor 39 by connecting it in series with the exciter 33.as shown in Figure 6 or in. any other manner. In Figures 6 and '7, I have shown details of a preferred mode of arranging the conductor 39 in inductive relation with the electrode.

As shown in Figures 6 and 7, the electrode is enclosed in an insulated sleeve 4| around which the conductor 39 is wound. As illustrated, one end of said conductor is adapted for connection with an end of the exciter wire 33, while the other end of the conductor 39 is disposed in closely spaced relationship with respect to the end of i the electrode exposed at one end of the sleeve ll.

The electrode and sleeve have interlocking portions comprising a bead 43 at the inner surface of the sleeve M and an annular groove 45 on the electrode to prevent longitudinal movement of the sleeve on the electrode and the sleeve is preferably provided with outstanding arms 41, the ends of which are adapted to bear against the sides of the electrode housing l6 in order to support the electrode in place therein. The sleeve is also provided with an upstanding ear 49 having a perforation or slot 5| adapted to receive an end of the conductor 39 in order to support it in spaced relationship with respect to the ex posed end of the electrode in order to provide the gap 31. If the conductor 39 is connected in series with the exciter 33, the currents traveling the exciter wire will also travel the conductor 39, which, being inductively coupled with the electrode, will heat the same by induction.

The electrode exciting devices 39 may be used entirely independently of the exciter 33 and have valuable application in devices of the character described even when and if actuated without a channel exciter 33.

In Figure 8 of the drawing, I have shown the possibility of so using the electrode exciting devices 39 by connecting their outer ends together through a suitable current limiting device 53, such as a resistor or choke.

The outer end of the conductor 39 may be connected with one side of a suitable source of electrical powersuch as a transformer winding, the other end of which is connected with the electrode in which case the electrode exciting device 39 will remain in continuous operation to heat the electrode.

By arranging the luminescent element of my present invention as aforesaid, I provide a preliminary path energizing means which, when the element is connected to a low voltage source of electrical supply, operates to condition the path to permit an electric discharge to be initiated or started in the path at relatively low voltage.

It is thought that the invention and numerous of its attendant advantages will be understood from the foregoing description and it is obvious that numerous changes may be made in the form, construction, and arrangement 01' the several parts without departing from the spirit or scope of my invention or sacrificing any of its attendant advantages, the form hereinbefore described being a preferred embodiment for the purpose of illustrating my invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is as follows:

1. A discharge device comprising a substantially cylindrical envelope sealed at its opposite ends, an integral partition extending from one sealed end to adjacent the other sealed end to provide in the tube a substantially U-shaped discharge channel, the arms of which are separated by said partition, an electrode within the channel at the extremities of each of said arms, and a conductor having an end portion disposed in closely spaced relationship with one of the electrodes, another end portion disposed in closely spaced relationship with respect to the other electrode, and an intermediate portion extending over said partition whereby to excite the atmosphere within the channel and permit an electrical discharge to be initiated in the channel between the electrodes upon the application 01' relatively low potential therebetween.

2. A discharge device comprising a sealed tubular element bent at its mid-portion to form a substantially U-shaped discharge channel, the arms of which are adjacently arranged, electrodes located at the extremities of said arms, a conductor having an end portion disposed in closely spaced relationship with one of the electrodes, another end portion disposed in ,closely spaced relationship with respect to the other electrode, and an intermediate portion extending in the U-shaped channel whereby to excite the atmosphere within the channel and permit an electrical discharge to be initiated in the channel between the electrodes upon the application of relatively low potential therebetween.

3. A discharge device comprising an envelope providing means forming a U-shaped discharge channel, the extremities of the arms or which channel are adjacently located, electrodes located in the extremities of the arms of the U-shaped channel, a conductor extending in said U-shaped channel and having its opposed ends disposed adjacent said electrodes to form relatively small gaps between the conductor and each electrode whereby when relatively low electrical potential is applied between the electrodes, said conductor will complete a circuit between the electrodes through arcing at the gaps between the conductor and the electrodes whereby the conductor may serve to excite the atmosphere within said channel and permit the initiation of an electrical discharge through said channel between the electrodes.

4. A discharge device comprising a tubular envelope formed to provide a sealed U-shaped discharge channel having arms separated by integral parts of the envelope forming a partition therebetween, an electrode associated with each arm and a conductor having a portion disposed in said channel in spaced relationship with respect to one of said electrodes and another por' tion disposed in spaced relationship with respec to the other electrode whereby to form gaps be tween each electrode and the conductor, the in termediate portions oi. said conductor being arranged to encircle said partition.

5. A discharge device comprising a tubulai envelope formed to provide a sealed U-shapec discharge channel having arms separated by integral parts of the envelope forming a partitior therebetween, an electrode associated with each arm and a conductor having a portion disposed in said channel in spaced relationship with respect to one of said electrodes and another portion disposed in spaced relationship with respeci to the other electrode whereby to form gaps between each electrode and the conductor, the intermediate portions oi said conductor extending outside of said envelope and arranged in coils encircling the same.

6. A discharge device comprising means forming an elongated channel having longitudinally extending dielectric means associated with said channel, said channel having associated means permitting electrical discharge in said channel and an exciter comprising a conductor encircling said dielectric means and adapted to carry high frequency electrical oscillations therein for initiating electrostatic efiects in said channel for the purpose of facilitating the initiation of electrical discharge therein.

7. A discharge device comprising means forming a discharge channel, an electrode disposed in said channel, a conductor coiled about said electrode and having a portion disposed in spaced relationship with respect to the electrode to provide a gap, means insulating the remaining portions of said conductor from said electrode, and means to connect said electrode in an external electrical circuit for the purpose of delivering electrical current to said electrode and conductor.

8. A discharge device comprising means forming a discharge channel, electrodes disposed in spaced relationship in said channel, each electrode having a conductor coiled thereabout with a portion of the conductor disposed in spaced relationship with respect to the electrode with which it is associated, means to connect the conductors associated with said electrodes together through a current-limiting device, and means to connect said electrodes in an external electrical circuit. I

9. A discharge device comprising means forming a channel, an electrode in said channel, an insulating sleeve disposed about said electrode, a conductor carried by said sleeve in inductive relationship with respect to the electrode and having a portion disposed in spaced relationship with respect to a portion of the electrode exposed by said sleeve to ailford an arcing gap between the electrode and said conductor, and

means to deliver electrical current through said electrode and conductor by causing arcing at said gap. i 10. A discharge device comprising means forming a channel, an electrode in said channel, an insulating sleeve enclosing said electrode, said sleeve and electrode having co-operating means preventing relative longitudinal movement there- 1 between, and said sleeve being formed with arms adapted to engage the walls of said channel to support the electrode in place therein, said sleeve exposing said electrode at an end thereof and having a conductor support, a conductor carried 1 by said sleeve in inductive relationship with respect to said electrode and having a portion mounted on said conductor support and carried in spaced position with respect to the exposedv ing a channel, an electrode in said channel, an

insulating sleeve enclosing said electrode, said sleeve and electrode having co-operating means preventing relative longitudinal movement therebetween, and said sleeve being formed with arms adapted to engage the walls of said channel to support the electrode in place therein, said sleeve exposing said electrode at an end thereof and having a conductor support, a conductor carried by said sleeve in inductive relationship with respect to said electrode, and means to deliver electrical current through said electrode and conductor.

13. A discharge device comprising means forming an elongated channel capable of carrying an electrical discharge, spaced electrodes associated with said channel, and an exciter comprising conductor means associated with said channel and adapted to carry electrical current for the purpose of exciting the channel to permit the initiation of electrical discharge therein at relatively low voltage, said conductor means having porticns disposed in position with respect to the electrodes to provide gaps between the electrodes and the conductor means, said envelope means comprising an elongated element bent upon itself between said spaced electrodes to provide substantially parallel legs having each an associated electrode.

14. A discharge device comprising means forming an elongated channel capable of carrying an electrical discharge, spacedelectrodes associated with said channel, and an exciter comprising conductor means associated with said channel and adapted to carry electrical current for the purpose of exciting the channel to permit the initiation of electrical discharge therein at relatively low voltage, said conductor means having portions disposed in position with respect to the electrodes to provide gaps between the electrodes and the conductor means, said channel being formed in the envelope with adjacent portions gaseous means capable of carrying an electronic discharge, and an exciter comprising an elongated conductor element in helical form encircling said channel portions, and adapted to carry high frequency electrical oscillations therein for the purpose of exciting the gaseous medium in the discharge device.

16. In combination, a discharge device comprising means forming an elongated channel containing gaseous means capable of carrying an electronic discharge, said channel being formed to provide adjacent channel portions, dielectric means between said channel portions, and an exciter, comprising conductor means, encircling said discharge device and adapted to carry high frequency electrical oscillations therein for the purpose of exciting the gaseous medium in the channel portions device.

17. An electric discharge tube which comprises an envelope containing a g ous filling, a pair of electrodes mounted within he envelope, means within the envelope for prolonging the path of the discharge from one electrode to the other, and an electro-conductive element extending irom one electrode to the other through the path of the discharge, the ends oi! said element being spaced a short distance from the electrodes.

18. An electric discharge tube which comprises an envelope containing a gaseous filling, a pair of electrodes mounted within the envelope, means within the envelope for prolonging the path of the discharge from one electrode to the other, and an electro-conductive element extending through the path of the discharge between the electrodes, said element being electrically disconnected from said electrodes.

19. An electric discharge tube which comprises an envelope containing a gaseous filling, a pair of electrodes mounted within the envelope, means within the envelope for prolonging the path .of the discharge from one electrode to the other, and an electro-conductive strip in the path of the discharge between the electrodes, said strip being electrically disconnected from said electrodes.

20. An electric discharge tube which comprises an envelope containing a gaseous filling, a pair of electrodes mounted within the envelope, means within the envelope for prolonging the path of the discharge from one electrode to the other, and a metallic strip extending along the path of the discharge between the electrodes, said strip being electrically disconnected from said electrodes. 21. An electric discharge tube which comprises an envelope containing a gaseous filling, a pair of electrodes mounted within the envelope, means within the envelope for prolonging the path of the discharge from one electrode to the other, and an electro-conductive element extending along the path of the discharge between the electrodes, said element having each end separated from an electrode by a small gap.

22. An electric discharge tube which comprises an envelope containing a gaseous filling, a pair of electrodes mounted within the envelope, means within the envelope for prolonging the path of the discharge from one electrode to the other, and an electro-conductive element extending along the path of the discharge between the electrodes, said element being attached to each electrode mechanically but insulated therefrom.

23. An electric discharge tube which comprises an envelope containing neon and provided with a base, a pair of electrodes within the envelope, means within the.envelope for prolonging the discharge between the electrodes, and an electroconductive element extending from one electrode to the other, said element extending along the path of the discharge between the electrodes and being without electrical connection to eitherelectrode.

24. An electric discharge tube which comprises an envelope containing a gas, a pair of spaced electrodes within the envelope, lead-in wires extending from the electrodes through the wall 0t the envelope for connection to a source of energy, and a pair of paths for the discharge between the electrodes, one path including the gas within the envelope and having a relatively high starting potential and a substantially falling voltage characteristic in operation, and the second path including a conductor in the envelope and without electrical connection to said electrodes, said conductor lying in the space in the envelope normally occupied by the discharge during operation, and said second path having a relatively low starting potential and a substantially rising voltage characterlstic in operation.

25. An electric discharge tube, which comprises an envelope containing a gas, a pair oi! spaced electrodes within the envelope, lead-in wires extending from the electrodes through the wall of the envelope for connection to a source 01' energy and a pair of paths for the discharge in parallel between the electrodes, the first or said paths having a positive voltage characteristic within the range or current values from zero to normal operating current and including a conductor within the envelope, electrically disconnected from the electrodes, and lying in the space in the envelope normally occupied by the discharge during operation, and the second path including said gas and having a negative voltage characteristic within said range.

26. An electric discharge tube which comprises an envelope containing a gas, a pair of spaced electrodes within the envelope, lead-in wires extending from the electrodes through the wall of the envelope for connection to a source of energy and a pair of paths for the discharge in parallel between the electrodes, the voltage characteristics of the two paths being convergent within the range of current values from zero to normal operating current, one path including a conductor within the envelope, electrically disconnected from the electrodes, and lying in the space in the envelope normally occupied by the discharge during operation.

2'7. An electric discharge tube which comprises an envelope containing a gas, a pair of spaced electrodes within the envelope, lead-in wires extending from the electrodes through the wall of the envelope for connection to a source of energy and a pair of paths or the discharge between the electrodes, the voltage characteristics of thetwo paths being convergent within the range of current values from zero to normal operating current, and having at least one value in common, one 01' said paths including a conductor within said envelope, electrically disconnected from the electrodes, and lying in the space normally occupied by the discharge during operation. I

, 28. An electric discharge tube which comprises an envelope containing a gas, a pair of spaced electrodes within the envelope, and means wholly within the tube and electrically disconnected from the electrodes for producing ions in the region within the tube between said electrodes, said means including a conductor lying in the space normally occupied by the discharge during operation.

29. An electric discharge tube which comprises an envelope containing a gas, a pair of spaced electrodes within the envelope, and a conductor within the tube electrically independent of the electrodes and extending'irom a point closely ad- Jacent to one electrode to a point closely adjacent to the other, said conductor lying in the space normally occupied by the discharge during operation or the tube.

30. An electric discharge tube, which comprises an envelope, 9. pair of spaced electrodes within the envelope, and a pair of paths for the discharge between the electrodes, one path consist ing of a body of gas and the other path including a conductor electrically disconnected from the electrodes and small gaps filled with the gas between the conductor and the electrodes, the conductor extending substantially the entire length of and in the space between the electrodes normally occupied by the positive column during operation or the tube.

31. An electric discharge device which comprises the combination of a glass envelope containing a gaseous filling at low pressure, a pair of spaced electrodes within said envelope, and an ionizingelement within said envelope extending between the electrodes and disconnected from at least one electrode, said element being of a material having a relatively low normal cathode fall of potential of'the order of less than about volts in said gaseous filling.

32. A discharge device comprising an envelope defining a sealed channel containing a gaseous medium adapted to be energized to sustain electrical discharges therein, said channel having portions disposed adjacently with dielectric means therebetween, spaced electrodes communicating with the adjacently disposed portions of the sealed channel to energize the gaseous medium therein, and an exciter operatively associated with said adjacently disposed channel portions.

33. A discharge device comprising an envelope defining channel portions containing a gaseous medium adapted to be energized to sustain electrical discharges therein, said channel having portions disposed adjacently, dielectric means interposed between said portions, cathode means in one of said portions adapted to be energized for electronic ionization, an anode in another of said portions, and exciter means operatively associated with said adjacently disposed channel portions.

34. In combination, a discharge device comprising means forming an elongated channel containing a gaseous medium capable of sustaining electrical discharge, spaced apart electrodes in said channel, means to apply electrical poten-- tial differences between said electrodes, and an exciter comprising a conductor encircling said discharge device, the opposite ends of said conductor being exposed within said channel and each end disposed in adjacent relationship with respect to one of said electrodes.

35. A gaseous conduction device comprising means forming a pair of elongated, adjacently extending gaseous conduction paths and an elongated embracing element arranged about said adjacently extending paths.

ROBERT E. BARCLAY. 

